The 3-D gait analysis of military load carriage is not well represented, if at all, within the available literature. This study collected 3-D lower limb kinematics and spatiotemporal parameters in order to assess the subsequent impact of carrying loads in a backpack of up to 32 kg. Results showed the addition of load significantly decreased the range of motion of flexion/extension of the knee and pelvic rotation. Also seen were increases in adduction/abduction and rotation of the hip and pelvis tilt. No changes to ankle kinematics were observed. Alterations to the spatiotemporal parameters of gait were also of considerable interest, namely, an increase in double support and a decrease in preferred stride length as carried load increased. Analysing kinematics during military or recreational load carriage broadens the knowledge regarding the development of exercise-related injuries, while helping to inform the human-centred design process for future load carrying systems. The importance of this study is that limited available research has investigated 3-D lower limb joint kinematics when carrying loads.

The effect of military load carriage on 3-D lower limb kinematics and spatiotemporal parameters

In the study, the influence of different boot prototype stiffness on gait kinematics and kinetics was investigated. The boot stiffness was determined by force-deformation measurement while pressing the foot model inserted into the boot by a custom-made robot. Gait analysis was carried out in nine neurologically intact subjects during walking while wearing two different boots with and without carrying a backpack, and differences were statistically tested using ANOVA. The results indicated distinctions in the boot shaft and vamp stiffness. The boot with a softer boot shaft enabled a wider range of motion in the ankle joint leading to more power generation in the ankle joint during the push-off, increased step length and gait velocity. The backpack mostly influenced the pelvis and trunk kinematics. The study has demonstrated the influence of boot shaft stiffness on biomechanical gait parameters and its importance for push-off that manufacturers should take into consideration when optimizing the footwear performance.

The influence of boot stiffness on gait kinematics and kinetics during stance phase

The aim of this systematic review was to evaluate the impact of bilaterally symmetrical backpack systems borne on the posterior trunk on walking biomechanics, as backpacks represent the most prevalent method of load carriage in the military and civilian population. A search of electronic databases was performed for studies that only investigated posteriorly-borne backpack carriage during level-grade walking (treadmill and over ground). Methodology of studies was assessed, and both meta-analysis and qualitative synthesis were completed. Fifty-four studies were included in this review. In summary, the available literature showed that backpack carriage in walking was associated with an increased trunk flexion angle, increased hip and ankle range of motion, increased vertical and horizontal ground reaction force, increased cadence, and reduced stride length. Several variations in backpack carriage protocols could explain between-study variations in results, including: walking speed, backpack carriage skill le...

The Effect of Backpack Carriage on the Biomechanics of Walking: A Systematic Review and Preliminary Meta-Analysis

Purpose: This study investigated the effects of carrying weighted backpacks of up to 20% of body weight on the posture and pain complaints of elementary-school children. Methods: Craniovertebral, forward trunk lean and pelvic tilt angles were measured from sagittal photographs of 62 children (8-11 years old) before and after walking while carrying backpacks containing 10%, 15%, or 20% of body weight. Pain severity after a 6-minute walk with the loaded backpack was recorded. Subjective complaints of pain were assessed using a visual analog scale after walking. Results: Repeated-measures ANOVA revealed statistically significant differences in postural angles and increased complaints of pain after walking with increased backpack loads. Conclusion: These results indicate that typical backpack loads create worsening postural changes due to backpack loads and time spent carrying those loads, putting children at increased risk for injury and pain, the latter of which is a strong predictor for back pain in adulthood.

Postural compensations and subjective complaints due to backpack loads and wear time in schoolchildren aged 8 to 11

Purpose: This study investigated the effects of carrying weighted backpacks of up to 20% of body weight on the posture and pain complaints of elementary-school children. Methods: Craniovertebral, forward trunk lean and pelvic tilt angles were measured from sagittal photographs of 62 children (8-11 years old) before and after walking while carrying backpacks containing 10%, 15%, or 20% of body weight. Pain severity after a 6-minute walk with the loaded backpack was recorded. Subjective complaints of pain were assessed using a visual analog scale after walking. Results: Repeated-measures ANOVA revealed statistically significant differences in postural angles and increased complaints of pain after walking with increased backpack loads. Conclusion: These results indicate that typical backpack loads create worsening postural changes due to backpack loads and time spent carrying those loads, putting children at increased risk for injury and pain, the latter of which is a strong predictor for back pain in adulthood. (Pediatr Phys Ther 2013;25:15‐24) Key words: back pain, biomechanics, child, female, human, lifting, male, pain, posture, risk factors, weight-bearing

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J. Brooke Metheny

Papers

Influence of carrying a backpack on pelvic tilt, rotation, and obliquity in female college students